1. Field of the Invention
The present invention relates, in general to music boxes and, in particular, to a new and useful improvement for the movement of a music box.
2. Description of the Prior Art
A movement of a conventional music box comprises a die-cast base, a diaphragm mounted on the base, a drum having an array of integral pins which are disposed on the drum periphery according to a predetermined program to operate or flip the diaphragm, and a gear train which drives the drum. These components are contained in a protective casing which may be molded from synthetic resin material. The resulting casing may be assembled into a doll or sewn toy. The base of such movement is formed as a die-cast work since a high rigidity and density is required to serve as a support for the diaphragm, which can be satisfied by a die-cast work. If the support for the diaphragm has a reduced rigidity and density, there results a poor resonance, which is inadequate to produce an amplified, clear tone. While this consideration justifies the use of a die casting for the base of the movement, it stands in the way of the simplification and economy of the manufacture and assembly of parts, thus limiting a possible reduction in the manufacturing cost.
Music toys are also known which involve a motion of the hand or foot of a doll as a music box is being played. In conventional music toys, the drive to move the hand or foot of a doll is derived from an external output shaft which is integrally embedded into the drum of the music box in alignment with the center axis thereof. Consequently, when the music box is to be used in a music toy, the drum must be specially designed for use in that music toy. This results in a complex production control and maintenance of the parts in the assembly line of music boxes. Additionally, since the output shaft has a varying length depending on the kind or specification of the music toys, it has been necessary to provide drums having different lengths for their output shafts.